The official recommendation is to switch to Firefox. Extension developers from Netscape’s development team have been working on creating Netstripe, a Firefox version of the Netscape 9 default theme. (Update (2010-05-12): Netstripe is gone; the Netscape Navigator and Messenger 9 themes were merged to create Simple Green.)
I used Netscape briefly to test website designs, back at version 8, and quit simply because it switched between the IE and Firefox rendering engines, providing no quirks of its own. Old browsers like Netscape 4, I’ve tossed already. I also used Mozilla for a time, and also quit that for similar reasons: Mozilla uses the same engine as Firefox, so rendering doesn’t change.
There will be a Netscape Archive for die-hard fans of the browser, where users will be able to download versions of the program, without support. Meanwhile, TechCrunch, Web Worker Daily (now merged into Gigaom), and Zoli Erdos all mourn the announcement. I wish I could share their feelings, but I’ve never really used Netscape; I most certainly didn’t start the Internet with it (that was horrid Internet Explorer), and now Firefox has begun climbing up the charts (16% last I heard, to IE’s 77%).
But in the interest of Internet history, let me say farewell, formally, to Netscape Navigator, and hope that its innovations will continue to be mirrored in all the competing programs that drove it out of business.